Dual band amplifier

• US 8,271,028 B2
• Filed: 06/24/2009
• Issued: 09/18/2012
• Est. Priority Date: 06/26/2008
• Status: Active Grant

• Current Assignee: SIGE Semiconductor Incorporated (Skyworks Solutions Incorporated)
• Original Assignee: SIGE Semiconductor Incorporated (Skyworks Solutions Incorporated)
• Inventors: Rabjohn, Gordon G.
• Primary Examiner(s): Nguyen, Lee
• Application Number:
  US12/490,638
• Publication Number:
  US 20090325527A1
• Time in Patent Office: 1,182 Days
• Field of Search: 455/281, 455/303, 455/306, 455/552.1, 455/553.1, 333/112, 333/124, 333/126, 333/129
• US Class Current: 455/552.1
• CPC Class Codes: H03F 3/191 Tuned amplifiers H03F3/193, H03F3/195 take precedence
• CPC Class Codes: H04B 1/0057 using diplexing or multiplexing filters for selecting the desired band

Abstract

A dual band amplifier is provided comprising a first matching circuit disposed in a first radiofrequency path between an input port and a first amplifier and a second matching circuit disposed in a second radiofrequency path between the input port and a second amplifier. The first matching circuit transforms a first input impedance of the first amplifier to a predetermined input port impedance when the radiofrequency signal is in a first frequency range and transmits the first input impedance to the input port when the radiofrequency signal is in the second frequency range. The second matching circuit transforms the second input impedance to the input port impedance when the input signal is in the second frequency range and transmits the second input impedance to the input port when the radiofrequency signal is in the first frequency range.

Claims

1. An electronic circuit comprising:

an input port for receiving a radiofrequency signal, the radiofrequency signal being in one of a first frequency range and a second frequency range, the first frequency range comprising frequencies higher than the frequencies of the second frequency range;

a first amplifier for generating a first output signal in dependence upon the radiofrequency signal when the radiofrequency signal is in the first frequency range, the first amplifier having a predetermined first input impedance;

a second amplifier for generating a second output signal in dependence upon the radiofrequency signal when the radiofrequency signal is in the second frequency range, the second amplifier having a predetermined second input impedance;

a first matching circuit disposed in a first radiofrequency path between the input port and the first amplifier, the first matching circuit for transmitting the first input impedance to the input port when the radiofrequency signal is in the second frequency range and for transforming the first input impedance to a predetermined input port impedance when the radiofrequency signal is in the first frequency range; and

,

a second matching circuit disposed in a second radiofrequency path between the input port and the second amplifier, the second matching circuit for transmitting the second input impedance to the input port when the radiofrequency signal is in the first frequency range and for transforming the second input impedance to the input port impedance when the input signal is in the second frequency range.

2. An electronic circuit as defined in claim 1 wherein the first amplifier and the second amplifier are low noise amplifiers.

3. An electronic circuit as defined in claim 1 wherein the first input impedance is determined such that the radiofrequency signal in the second frequency range is reflected and wherein the second input impedance is determined such that the radiofrequency signal in the first frequency range is reflected.

4. An electronic circuit as defined in any one of claims 1 to 3 wherein the first matching circuit comprises a low pass filter and wherein the second matching circuit comprises a high pass filter.

5. An electronic circuit as defined in claim 4 wherein the low pass filter has a predetermined first low pass filter reactance in the first frequency range for matching the first input impedance to the input port impedance and a predetermined second low pass filter reactance in the second frequency range for transmitting the first input impedance to the input port and, the high pass filter has a predetermined first high pass filter reactance in the first frequency range for transmitting the second input impedance to the input port and a predetermined second high pass filter reactance in the second frequency range for matching the second input impedance to the input port impedance.

6. An electronic circuit as defined in claim 5 wherein the low pass filter includes an inductor disposed in the first radiofrequency path and a capacitor connecting the first radiofrequency path to ground and,

wherein the high pass filter comprises a capacitor disposed in the second radiofrequency path and an inductor connecting the second radiofrequency path to ground.

7. An electronic circuit as defined in claim 6 wherein the low pass filter includes a first blocking capacitor disposed in the first radiofrequency path and, the high pass filter includes a second blocking capacitor disposed in series with the inductor.

8. An electronic circuit as defined in any one of claims 1 to 3 wherein the first amplifier and the second amplifier includes a first amplifier transistor and a second amplifier transistor, respectively.

9. An electronic circuit as defined in claim 8 wherein the first radiofrequency path is connected to a control terminal of the first amplifier transistor and the second radiofrequency path is connected to a control terminal of the second amplifier transistor.

10. An electronic circuit as defined in claim 9 wherein the control terminal of the first amplifier transistor and the control terminal of the second amplifier transistor is one of a gate of a field effect transistor and a base of a bipolar junction transistor.

11. An electronic circuit as defined in claim 9 further comprising control circuitry for switchably enabling the first amplifier transistor when the radiofrequency signal is in the first frequency range and for switchably enabling the second amplifier transistor when the radiofrequency signal is in the second frequency range.

12. An electronic circuit as defined in claim 11 wherein the control circuitry includes a high band gate bias circuit connected to the first radiofrequency path and a low band gate bias circuit connected to the second radiofrequency path.

13. An electronic circuit as defined in claim 12 wherein the control circuitry includes a first source switch transistor connected to a source of the first amplifier transistor and a second source switch transistor connected to a source of the second amplifier transistor.

14. An electronic circuit as defined in claim 8 wherein the first amplifier includes a cascade amplifier.

15. An electronic circuit as defined in claim 8 wherein the first amplifier transistor and the second amplifier transistor include a field effect transistor.

16. An electronic circuit as defined in claim 15 wherein the first source switch transistor and the second source switch transistor include a field effect transistor.

17. An electronic circuit comprising:

an input port for receiving a radiofrequency signal, the radiofrequency signal being in one of a first frequency range and a second frequency range, the first frequency range comprising frequencies higher than the frequencies of the second frequency range;

a first amplifier transistor for generating a first output signal in dependence upon the radiofrequency signal when the radiofrequency signal is in the first frequency range, the first amplifier transistor having a first input impedance, the first input impedance being sufficient for reflecting the radiofrequency signal in the second frequency range;

a second amplifier transistor for generating a second output signal in dependence upon the radiofrequency signal when the radiofrequency signal is in the second frequency range, the second amplifier transistor having a second input impedance, the second input impedance being sufficient for reflecting the radiofrequency signal in the first frequency range;

a low pass filter disposed in a first radiofrequency path between the input port and a control terminal of the first amplifier transistor, the low pass filter having a predetermined first low pass filter reactance in the first frequency range for matching the first input impedance to a predetermined input port impedance and a predetermined second low pass filter reactance in the second frequency range for transmitting the first input impedance to the input port; and

,

a high pass filter disposed in a second radiofrequency path between the input port and a control terminal of the second amplifier transistor, the high pass filter having a predetermined first high pass filter reactance in the first frequency range for transmitting the second input impedance to the input port and a predetermined second high pass filter reactance in the second frequency range for matching the second input impedance to the input port impedance.

18. An electronic circuit as defined in claim 17 wherein the control terminal of the first amplifier transistor and the control terminal of the second amplifier transistor is one of a gate of a field effect transistor and a base of a bipolar junction transistor.

19. An electronic circuit as defined in claim 17 further comprising control circuitry for switchably enabling the first amplifier transistor when the radiofrequency signal is in the first frequency range and for switchably enabling the second amplifier transistor when the radiofrequency signal is in the second frequency range.

20. An electronic circuit as defined in claim 19 wherein the control circuitry includes a high band gate bias circuit connected to the first radiofrequency path and a low band gate bias circuit connected to the second radiofrequency path.

21. An electronic circuit as defined in claim 20 wherein the control circuitry includes a first source switch transistor connected to a source of the first amplifier transistor and a second source switch transistor connected to a source of the second amplifier transistor.

22. An electronic circuit as defined in any one of claims 17 to 21 wherein the low pass filter includes an inductor disposed in the first radiofrequency path and a capacitor connecting the first radiofrequency path to ground and the high pass filter comprises a capacitor disposed in the second radiofrequency path and an inductor connecting the second radiofrequency path to ground.

23. An electronic circuit as defined in claim 22 wherein the low pass filter includes a first blocking capacitor disposed in the first radiofrequency path and the high pass filter includes a second blocking capacitor disposed in series with the inductor.

24. A storage medium having stored therein executable commands for execution on a processor, the executable commands for when executed resulting in an electronic circuit design comprising:

an input port for receiving a radiofrequency signal, the radiofrequency signal being in one of a first frequency range and a second frequency range, the first frequency range including frequencies higher than the frequencies of the second frequency range;

a first amplifier transistor for generating a first output signal in dependence upon the radiofrequency signal when the radiofrequency signal is in the first frequency range, the first amplifier transistor having a first input impedance, the first input impedance being sufficient for reflecting the radiofrequency signal in the second frequency range;

a second amplifier transistor for generating a second output signal in dependence upon the radiofrequency signal when the radiofrequency signal is in the second frequency range, the second amplifier transistor having a second input impedance, the second input impedance being sufficient for reflecting the radiofrequency signal in the first frequency range;

a low pass filter disposed in a first radiofrequency path between the input port and a control terminal of the first amplifier transistor, the low pass filter having a predetermined first low pass filter reactance in the first frequency range for matching the first input impedance to a predetermined input port impedance and a predetermined second low pass filter reactance in the second frequency range for transmitting the first input impedance to the input port; and

,

a high pass filter disposed in a second radiofrequency path between the input port and a control terminal of the second amplifier transistor, the high pass filter having a predetermined first high pass filter reactance in the first frequency range for transmitting the second input impedance to the input port and a predetermined second high pass filter reactance in the second frequency range for matching the second input impedance to the input port impedance.

25. A method comprising:

receiving a control signal indicative of a radiofrequency signal being in one of a first frequency range and a second frequency range;

turning ON one of a first amplifier and a second amplifier in dependence upon the control signal;

receiving the radiofrequency signal;

if the radiofrequency signal is in the first frequency range, transforming a predetermined first input impedance of the first amplifier to match a predetermined impedance of an input port for receiving the radiofrequency signal and transmitting a predetermined second input impedance of the second amplifier to the input port;

if the radiofrequency signal is in the second frequency range, transforming the second input impedance of the second amplifier to match the impedance of the input port and transmitting the first input impedance of the first amplifier to the input port; and

,

processing the radiofrequency signal using the turned ON one of the first amplifier and the second amplifier.

26. A method as defined in claim 25 wherein the first frequency range includes frequencies higher than the frequencies of the second frequency range the first input impedance is one of transformed and transmitted using a low pass filter disposed in a first radiofrequency path connecting the input port with the first amplifier, and the second input impedance is the other one of transformed and transmitted using a high pass filter disposed in a second radiofrequency path connecting the input port with the second amplifier.

27. A method as defined in claim 26 wherein the first amplifier and the second amplifier includes a first amplifier transistor and a second amplifier transistor, respectively, a source of the first amplifier transistor and the second amplifier transistor being connected to a first source switch transistor and a second source switch transistor, respectively.

28. A method as defined in claim 27 further comprising turning OFF the one of the first source switch transistor and the second source switch transistor followed by turning OFF the respective amplifier transistor.

29. The method according to claim 27 further comprising turning ON one of the first source switch transistor and the second source switch transistor in dependence upon the control signal prior to turning ON the one of the first amplifier and the second amplifier.

30. A method as defined in claim 26 wherein the first amplifier and the second amplifier include a first amplifier transistor and a second amplifier transistor, respectively, and the method further comprises turning ON in dependence upon the control signal one of a first bias circuit and a second bias circuit connected to the first radiofrequency path and the second radiofrequency path, respectively.